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Letters PatentNo. 81,664, dated September 1', 1868;

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tro ALL-WHOM 1T MAY CONCERN:

l Be it known that I, JAMES C. MILLEnD, of River Point, in the county of Kent, and State of Rhode Island, have invented a new and useful Improvement in Boring-Tools; and I doherebydeclarethat the following is a full, clealgand exact description thereof, which will enable others `skilled inthe art to make and use the same, reference being had to the accompanying drawings, forming part-of this specification, in which- A Figure 1 is aside view of my improved boring-tool, with a portion of the holder broken away, to exhibit the construction and arrangement oi' the cutters.

Figure 2 is a longitudinal section of the tool'through the line a: :u of lig. 1.

Figure 3 is a view ofthe adjusting-key.`

Similarlettersef reference indicate like parts. l

The object ,of4 this invention is to provide' ai simple and effective. tool for boring out holes in casting and other iron work. I v l It consists, in general terms, of a pair' of stud-cutters 'or -boring-plates, held in a mortise or rectangular eye in the end of a metal shank, and arranged at right angles to the axis of the shank, so-that the said boringplates will pass in contact with each other, when being kset out or in byan adjusting-screw.

In the drawings, A is the shank ofthe tool, a stout metal rod, and is formed with a mortise or rectangular eye, the width of which is just equal to twice the thickness of one of the boring-plates B, so that thelatter,

when in Contact side by side with each other, may just fit ,within the mortise, as shown.

` The length-of the mortisejust equals the width of the borin`gplates.

The plates are set out 014 in by a-right-and-left-threaded screw, a, which rests in the semi-cylindrical face e oithe block b..v I

This 'screw-,1 when turned in the face of the block, actuates the plates B B, for at the lower proximate cornersl of the plates are formed corresponding hollow threads, extending one-quarter of a circle, as shown at d, which, together, makeup the halt' of a hollow thread.`4

The face of the block b and this hollow thread thusenclose theserew, and hold it in place. It is kept from longitudinal movementzby acollar, e, atlixed` across .the middle of the facce, and which its'on the neck connecting the right-and-l'eft-hand thread of the screw.

The block bis formed with lanehes,f f, which tit against the surface adjacent to the mortise, and serve to hold the 'block in place. I v l The mortise is wider than the seat oi the block b, so that the block may be withdrawn by lifting it out ot' its seat, thus bringingfthe anehesup to where the width ot' themortise will permit them to passthrough it.

The plates are elamped'rmly in place, when set out orin to the proper distance, bya capstan-lieaded setserew, D, arranged with its point acting against the bottom of the block'b, through a hollow-thread in the shank at that point, the said hollow thread opening into the mortise, and downward into a recess'or spring, C, in the Y shank, so as to render the head ofthe set-serew accessible with a key, E, (shown at Figure-4.)

This key is formed with a square end, g, for inserting in a square hole in the end of the screw a, to turn the latter. The round end, h, is inserted inthe holes of the head'ot' the set-screw D, when the latter is to be turned to clamp or loosen the plates B, The edges z'z'uof the plates are-bevelled, to present the proper cuttingedge to the work. lI i I This tool isV used in the same manner as other boring-tools of analogous nature.

m mjare the shoulders eonnectingthe seat of the block with the mortise proper'.`

'Having thus described ,my invention, I claim as new, and desire tosecure by'Letters Patent- 1. `The combination, in a boring-tool, ofthe boring-plates B B, right-and-left-handed screw a, and block` b, when operatingptogether within amortise or eye inthe shank A, all substantially as shown and described, and vfor the purpose lset forth.

2. The set-serew D, arranged to operate in combination with the above-claimed parts, substantially as herein described. JAMES G'MILLERD.

Witnesses:

IRA O; ASEAMANS, Jenn B. ALLEN. 

